Nonspill vent plug



meu L" NONSPILL VENT PLUG Filed Jan. 3, 1958 Patentedy Dec. 26, 1939 ATET FFiCE NGNSPILL VENT PLUG Joseph Lester Woodbridge, Philadelphia, Pa., asignor to The Electric Storage Battery Company, Philadelphia, Pa., a corporation of New Jersey Application `lanuary 3,

6 Claims.

rfhis vent plug is an improvement, the irnreznent comprising a modification in the o1' the valve member to provide greater tilted without increasing the diameter of the plug. in the present application, the valve inemboundcd'by a plane surface and two conhich the valve member rolls whenthe plusr is tilted andthe other of longer radius but with. the saine center, this latter spherical surface being arranged to close the orifice in the valve seat when the plug is tilted. vVlith this modification in the design of the valve member, its center of gravity moved further away from the center: of the spherical surfaces so that the Valve menom ber will roll over to close the valve with less angular displacement of the plug from the vertical position, and when the plug has been ytilted through a given angle,fthe moment ofweight will Fig. 2 is a view with parts broken away in longitudinal cross-section showing the vent plug in tilted position.

In the drawing, l represents the vent plug generally which is preferably cylindrical in shape and is provided with a depending, cylindrical projection 2 externally threadedV for engagement with the internal threads `of an appropriate vent opening in the cover of a storage battery cell (not shown) A shoulder 3 is pro-vided to which is applied a soft rubber gasket 4 to provide an air-tight seal between the vent plug and the cell cover.

The vent plug is hollow, having a lower cylindrical chamber 5 and an upper cylindrical charnber 6 separated by an annularpartition meniber l whose external threads 8 engage corresponding threads on the internal wall oi the vent plug. The partition member 'l is provided with an axial orifice providing communication between the lower chamber 5-and the upper charnber of the vent plug. The uppersurface of the partition member l is conical as at l, while the.

lower surface lies in a horizontal plane as at il, and is provided with a lip or boss l2 surrounding 1938, Serial No. 183,016 (C1. 251-447) the opening S and forming an abutment for the pliable valve seat i3. The partition member 3 is provided with a shoulder which seats on the shoulder i5 of the internal wall of the vent plug and is also provided with a depending skirt Hi having an inturned ledge il which supports the pliable valve seat 53 normally' out of contact with. the lip ill. The valve seat I3 has an axial orifice ig confronting the orifice 9 in the partition member l. Recesses 45 are provided at diametrically opposite points in the conical surface of the partition 'i to facilitate inserting and removing this member by means of a suitable tool such as a screw driver.

The lower chamber 5 is provided with an internal horizontal shoulder i9 surr .'lndng the cylindrical passage 2c passing through the depending projection 2 and thus providing com' munication with the interior ci the cell when the vent plug is in place in the cell cover.

rIhe vent plug is surrnounted by a cap E9 closing the top of the upper chamber 5 except for the vent duct Zit in the depending vent tube 3l, having horizontal passages 32 leading from the vent duct EG into the chamber il. The vent duct it is closed atthe bottom and spray baiiles 33 are provided above and below the horizontal passagesiZ.

Within the lower *chamber 5 valve member 2i. This valve member is bounded by a lower plane surface 2li and `by two spherical surfaces 2? and 23a. In the normal position of the valve member, the plane surface 2li rests on the shoulder i9 and the spherical surface closely iits the internal cylindrical wall of the chamber 5, lallowing just enough clearance to perrnit the valve member to roll along the cylindrical wall when theV vent plug is tilted through a sufficient angle. It is not absolutely necessary that the upper surface of the shoulder E3 and the lower surface of the valve member 2l should be exactly plane. They might be slightly conical and still give satisfactory results. When the valve member rolls along the cylindrical wall of the chamber 5 as a result of the tilting of the plug, the spherical surface 23a comes into contact with the lower surface of the valve seat i3 and. closes the orice i8 as shown in Fig. 2.

The spherical surfaces 23 and figa have a coinmon center indicated at 22, and between these two spherical surfaces there is provided a conical band it .so designed that this part of the surface cf the valve member cannot come oontac't with the cylindrical wall of the chamber 5' when the plug is tilted as shown in Fig. 2. The

is located the center of gravity of the valve member is indicated at the point 35 which, by reason of the design of the valve member, is displaced by an appreciable distance from the center 22 of the spherical surfaces.

It will be noted that, as the plug is tilted from the vertical position lto a position where the valve member begins to roll on the cylindrical wall of the chamber 5, the point of contact between the valve member and the cylindrical wall will always be in a line passing through the center 22 and extending at right angles to the cylindrical Wall as illustrated by the line III in Fig. 2. The force of gravity tending to roll the valve member will be in a vertical line passing through the center of gravity as illustrated by the line d2 in Fig. 2. The gravitational moment tending to roll the valve member and cause it to close the orice I8 in the Valve seat I3 will therefore be the product of the weight of the valve member and the distance between the line 42 and the point of contact 43, this distance or lever arm being represented by the line 44 in Fig. 2. It is evident, therefore, that the greater the distance between the center of gravity 35 and the center 22 of the spherical surface on which the valve member rolls, the greater will be the lever arm lIll and the resultant gravitational moment which forces the valve member against the valve seat I3. The design of the valve member herein disclosed is adapted to provide the maximum distance between the point 35 and the point 22 with given dimensions of the plug. This feature is of importance where available space for the plug is limited and certain dimensions cannot be eX- ceeded.

The valve member is provided with an axial cylindrical cavity 25 which is designed to remove as much weight as possible below the center point 22 and therefore displace the center of gravity 35 asv far as possible from the center 22. Two cylindrical ducts 2l and 28 are provided extending from the cavity 25 to the external surface of the valve member between that portion of the spherical surface 23 on which the Valve member rolls along the cylindrical wall of the chamber 5 and that portion of the spherical surface 23a which closes the orifice I8 as shown in Fig. 2.

In the normal upright position of the Vent plug, seen in Fig. l, there is provided a passage for the escape of gas from the cell through the duct 2B, the cavity 25, the ducts 21 and 28 in the valve member and the openings I8 and 9 in the valve seat and the partition member into the upper chamber I and from there through orifice 32 and vent duct 30 into the atmosphere. When the cell is tilted through a suflicient angle, the valve member ZI will roll into the position shown in Fig. 2, closing the orice I8 and bringing the valve seat I3 against the annular lip I2 so as to close the passage between the chamber 6 and the chamber 5 and prevent the escape of liquid from the cell.

The depending skirt I4 is provided with a number of radial openings or slots 34. 'Ihe object of these slots is to provide a path for draining back any liquid which may collect in the chamber 6, whether by failure ofthe valve member to close the opening I8 completely or by reason of the trapping of spray from the cell during the gassing period of charge.l Since there is usually a certain amount of gas developed in a storage cell even when standing idle, it is necessary to provide for the drainage of this trapped liquid against the escape of gas bubbles through the opening I8. This is provided for by the space between the disk I3 and the underside of the partition l, which space communicates with the slotsl 34, allowing the trapped liquid to pass down around the valve member 2| while the gas bubbles are escaping through the orifices 21 and 28 in the valve member and through the opening I8 in the disk I3. To further provide for this drainage of trapped liquid, one or more capillary grooves are provided in the upper surface of the shoulder I9 as indicated at 36. The groove 36 is continued as a vertical groove 31 in the cylindrical wall of the passage 20. It will thus be seen that there is provided a substantially continuous capillary path for the drainage of trapped liquid from the chamber 6 via the space II, groove 34, the restricted space between the valve member 2| and the cylindrical wall surrounding it, 'the grooves 36 and 31, while gas is free to escape from the cell through the various ducts and passages already described.

The design and dimensions of the several parts of the device are such that, when the valve member ZI is in the position indicated in Fig. 2 corresponding to the limit of its travel in the direction toward the valve seat, the distance from the cen-v ter 22 of its spherical surface to the inner edge of the shoulder I9 is less than the radius of the spherical surface, thus preventing the valve member 2I from rotating into a position from which it cannot roll back into its normal position supported on the shoulder I9 when the vent plug is restored to its upright position.

The ducts 2l and 28 through the valve member 2I are so located that, when the'valve member has rolled into the position indicated in Fig. 2, neither of these ducts will overlap the opening I8 in the valve seat and allow liquid to escape in *the tilted position of the vent plug.

The valve member 2 I should preferably be made of relatively heavy material such as lead-'antimony alloy.

The baille p1ates`33 surrounding the vent tube lasy 3I above and below the openings 32 prevent any liquid trapped in they chamber 6 from flowing across the openings 32 in the various positions of the plug in serviceV where this liquid might be ejected through the duct `3E) by any gas escapingk from the cell. l

I do not intend to be limited save as the scope of the prior art and o-f the attached claims may require.

I claim: v

l. In a nonspill vent plug, a cylindrical wall defining a chamber, a pliable valve seat having an orice and supported above the chamber, an internal supporting ledge at the botto-m of the chamber, and a perforated valve member bounded by a substantiallyat surface and two concentric spherical surfaces having radii of different lengths of which the lesser is only slightly less than that of the cylindrical, wall, thereby preventing lateral displacement, said valve member normally resting with its flat surface on the -supporting ledge and adapted when the vent plug is tilted to roll on its spherical surface of lesser radius along the cylindrical wall tobring its spherical surface of greater radius against the valve seat to close the orice.

2. In a nonspill vent plug, a cylindrical wall defining a chamber, a pliable Valve seat having an oriice and supported above the chamber, an

internal supporting ledge at the bottom of the chamber, and a perforated valve member normally supported on the ledge vand having an annular spherical surface of `radius only slightly less than that of the cylindrical Wall on which surface the valve ,member is adapted Without appreciable lateral displacement to roll along the cylindrical Wall toward the valve seat when the plug is tilted and said valve member having a second spherical surface concentric with but of greater radius than the first-named spherical surface, said second spherical surface so located as to contact with the valve seat to close the orifice when the valve member` has rolled in response to tilting of the plug, the center of gravity of the valve member being axiallydisplaced a substantial distance from the 'center of the spherical surfaces.

3. For storage batteries, a nonspill vent plug having a chamber provided with an inlet and an outlet, and a movable perforated valve member located in said chamber and having a surface which supports it in relatively stable position when said vent plug is vertical and having a second surface in the shape of the segment of a sphere at the rim of said first surface closely fitting and arranged for rolling Contact with the Wall of said chamber Without appreciable lateral displacement When said plug is tilted and having another imperforate spherical surface concentric with the second surface and of greater radius arranged upon the rolling of said valve member to close the outlet from said chamber.

4. For storage batteries, a nonspill vent plug having a chamber provided with an inlet, a partition member having an orifice therein providing an eXit from said chamber, and a perforated valve member normally located in relatively stable position in said chamber when said plug is vertical and having a surface in the shape of the segment of a sphere of suicient radius to prevent appreciable lateral displacement arranged to roll on the inner surfaces of said plug when said plug is tilted and having another imperforate spherical surface concentric with the first-mentioned spherical surface and of greater radius arranged to close said exit when said plug is tilted.

5. For storage batteries, a nonspill vent plug having a chamber therein, a partition member having an orice therein providing an exit from said chamber, and a valve member normally located in relatively stable position in said chamber when said plug is vertical and having an annular curved surface confronting the Walls of said chamber and arranged to roll on the Walls of said chamber When said plug is tilted and having a second surface in the shape of a portion of a sphere and arranged to contact With and close said exit when said plug is tilted, said valve member being provided with a branching conduit through it having communication at one end with the supporting surface of said valve member and having communication at its other ends with the surface of said valve member between said annular surface and said second surface.

6. For storage batteries, a nonspill vent plug having a chamber provided with an inlet, a partition member having an orifice providing an outlet from said chamber, a valve member normally located in relatively stable position in said chamber when said plug is vertical and having a surface in the shape of the segment of a sphere, of suiicient radius to prevent appreciable lateral displacement, arranged to roll on inner surfaces of said plug when the plug is tilted and having another spherical surface concentric with the first-mentionedv spherical surface and of greater radius and arranged to close said outlet when said plug is tilted, and means permitting fluid flow from said inlet to said partition member.

JOSEPH LESTER WOODBRIDGE. 

